Building Resonance Structures with Similar Formal Charges

[Ayesha Aslam-Mir 3C]

In building resonance structures with similar distributions of formal charges, how do we determine which is more favorable? I've looked at a few problems with different double/single bonds, same distributions of formal charges, and remember reading somewhere that favorability is influenced by least overall formal charges. I also remember reading that the formal charges need to make sense depending on an atom's individual electronegativity, so I was wondering if anyone would be able to clear that up? Thanks!

[Kainalu Puu-Robinson]

As you said, favorability is influenced by the least overall formal charges. I find it easiest to just visually look at the completed Lewis structures with the formal charges and see which one has the least formal charges.

[Mahnoor_Wani_1I]

Least formal charges = more favorable. More electronegative atom should have the negative charge since it attracts electrons. If mot electronegative atom doesn't have the negative charge then its not favorable